<?php
/**
 * Zend Framework
 *
 * LICENSE
 *
 * This source file is subject to the new BSD license that is bundled
 * with this package in the file LICENSE.txt.
 * It is also available through the world-wide-web at this URL:
 * http://framework.zend.com/license/new-bsd
 * If you did not receive a copy of the license and are unable to
 * obtain it through the world-wide-web, please send an email
 * to license@zend.com so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 * @version    $Id: Wildcard.php 18954 2009-11-12 20:01:33Z alexander $
 */


/** Zend_Search_Lucene_Search_Query */
require_once 'Zend/Search/Lucene/Search/Query.php';


/**
 * @category   Zend
 * @package    Zend_Search_Lucene
 * @subpackage Search
 * @copyright  Copyright (c) 2005-2009 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */
class Zend_Search_Lucene_Search_Query_Wildcard extends Zend_Search_Lucene_Search_Query
{
	/**
	 * Search pattern.
	 *
	 * Field has to be fully specified or has to be null
	 * Text may contain '*' or '?' symbols
	 *
	 * @var Zend_Search_Lucene_Index_Term
	 */
	private $_pattern;

	/**
	 * Matched terms.
	 *
	 * Matched terms list.
	 * It's filled during the search (rewrite operation) and may be used for search result
	 * post-processing
	 *
	 * Array of Zend_Search_Lucene_Index_Term objects
	 *
	 * @var array
	 */
	private $_matches = null;

	/**
	 * Minimum term prefix length (number of minimum non-wildcard characters)
	 *
	 * @var integer
	 */
	private static $_minPrefixLength = 3;

	/**
	 * Zend_Search_Lucene_Search_Query_Wildcard constructor.
	 *
	 * @param Zend_Search_Lucene_Index_Term $pattern
	 */
	public function __construct(Zend_Search_Lucene_Index_Term $pattern)
	{
		$this->_pattern = $pattern;
	}

	/**
	 * Get minimum prefix length
	 *
	 * @return integer
	 */
	public static function getMinPrefixLength()
	{
		return self::$_minPrefixLength;
	}

	/**
	 * Set minimum prefix length
	 *
	 * @param integer $minPrefixLength
	 */
	public static function setMinPrefixLength($minPrefixLength)
	{
		self::$_minPrefixLength = $minPrefixLength;
	}

	/**
	 * Get terms prefix
	 *
	 * @param string $word
	 * @return string
	 */
	private static function _getPrefix($word)
	{
		$questionMarkPosition = strpos($word, '?');
		$astrericPosition     = strpos($word, '*');

		if ($questionMarkPosition !== false) {
			if ($astrericPosition !== false) {
				return substr($word, 0, min($questionMarkPosition, $astrericPosition));
			}

			return substr($word, 0, $questionMarkPosition);
		} else if ($astrericPosition !== false) {
			return substr($word, 0, $astrericPosition);
		}

		return $word;
	}

	/**
	 * Re-write query into primitive queries in the context of specified index
	 *
	 * @param Zend_Search_Lucene_Interface $index
	 * @return Zend_Search_Lucene_Search_Query
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function rewrite(Zend_Search_Lucene_Interface $index)
	{
		$this->_matches = array();

		if ($this->_pattern->field === null) {
			// Search through all fields
			$fields = $index->getFieldNames(true /* indexed fields list */);
		} else {
			$fields = array($this->_pattern->field);
		}

		$prefix          = self::_getPrefix($this->_pattern->text);
		$prefixLength    = strlen($prefix);
		$matchExpression = '/^' . str_replace(array('\\?', '\\*'), array('.', '.*') , preg_quote($this->_pattern->text, '/')) . '$/';

		if ($prefixLength < self::$_minPrefixLength) {
			require_once 'Zend/Search/Lucene/Exception.php';
			throw new Zend_Search_Lucene_Exception('At least ' . self::$_minPrefixLength . ' non-wildcard characters are required at the beginning of pattern.');
		}

		/** @todo check for PCRE unicode support may be performed through Zend_Environment in some future */
		if (@preg_match('/\pL/u', 'a') == 1) {
			// PCRE unicode support is turned on
			// add Unicode modifier to the match expression
			$matchExpression .= 'u';
		}

		$maxTerms = Zend_Search_Lucene::getTermsPerQueryLimit();
		foreach ($fields as $field) {
			$index->resetTermsStream();

			require_once 'Zend/Search/Lucene/Index/Term.php';
			if ($prefix != '') {
				$index->skipTo(new Zend_Search_Lucene_Index_Term($prefix, $field));

				while ($index->currentTerm() !== null          &&
				$index->currentTerm()->field == $field  &&
				substr($index->currentTerm()->text, 0, $prefixLength) == $prefix) {
					if (preg_match($matchExpression, $index->currentTerm()->text) === 1) {
						$this->_matches[] = $index->currentTerm();

						if ($maxTerms != 0  &&  count($this->_matches) > $maxTerms) {
							require_once 'Zend/Search/Lucene/Exception.php';
							throw new Zend_Search_Lucene_Exception('Terms per query limit is reached.');
						}
					}

					$index->nextTerm();
				}
			} else {
				$index->skipTo(new Zend_Search_Lucene_Index_Term('', $field));

				while ($index->currentTerm() !== null  &&  $index->currentTerm()->field == $field) {
					if (preg_match($matchExpression, $index->currentTerm()->text) === 1) {
						$this->_matches[] = $index->currentTerm();

						if ($maxTerms != 0  &&  count($this->_matches) > $maxTerms) {
							require_once 'Zend/Search/Lucene/Exception.php';
							throw new Zend_Search_Lucene_Exception('Terms per query limit is reached.');
						}
					}

					$index->nextTerm();
				}
			}

			$index->closeTermsStream();
		}

		if (count($this->_matches) == 0) {
			require_once 'Zend/Search/Lucene/Search/Query/Empty.php';
			return new Zend_Search_Lucene_Search_Query_Empty();
		} else if (count($this->_matches) == 1) {
			require_once 'Zend/Search/Lucene/Search/Query/Term.php';
			return new Zend_Search_Lucene_Search_Query_Term(reset($this->_matches));
		} else {
			require_once 'Zend/Search/Lucene/Search/Query/MultiTerm.php';
			$rewrittenQuery = new Zend_Search_Lucene_Search_Query_MultiTerm();

			foreach ($this->_matches as $matchedTerm) {
				$rewrittenQuery->addTerm($matchedTerm);
			}

			return $rewrittenQuery;
		}
	}

	/**
	 * Optimize query in the context of specified index
	 *
	 * @param Zend_Search_Lucene_Interface $index
	 * @return Zend_Search_Lucene_Search_Query
	 */
	public function optimize(Zend_Search_Lucene_Interface $index)
	{
		require_once 'Zend/Search/Lucene/Exception.php';
		throw new Zend_Search_Lucene_Exception('Wildcard query should not be directly used for search. Use $query->rewrite($index)');
	}


	/**
	 * Returns query pattern
	 *
	 * @return Zend_Search_Lucene_Index_Term
	 */
	public function getPattern()
	{
		return $this->_pattern;
	}


	/**
	 * Return query terms
	 *
	 * @return array
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function getQueryTerms()
	{
		if ($this->_matches === null) {
			require_once 'Zend/Search/Lucene/Exception.php';
			throw new Zend_Search_Lucene_Exception('Search has to be performed first to get matched terms');
		}

		return $this->_matches;
	}

	/**
	 * Constructs an appropriate Weight implementation for this query.
	 *
	 * @param Zend_Search_Lucene_Interface $reader
	 * @return Zend_Search_Lucene_Search_Weight
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function createWeight(Zend_Search_Lucene_Interface $reader)
	{
		require_once 'Zend/Search/Lucene/Exception.php';
		throw new Zend_Search_Lucene_Exception('Wildcard query should not be directly used for search. Use $query->rewrite($index)');
	}


	/**
	 * Execute query in context of index reader
	 * It also initializes necessary internal structures
	 *
	 * @param Zend_Search_Lucene_Interface $reader
	 * @param Zend_Search_Lucene_Index_DocsFilter|null $docsFilter
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function execute(Zend_Search_Lucene_Interface $reader, $docsFilter = null)
	{
		require_once 'Zend/Search/Lucene/Exception.php';
		throw new Zend_Search_Lucene_Exception('Wildcard query should not be directly used for search. Use $query->rewrite($index)');
	}

	/**
	 * Get document ids likely matching the query
	 *
	 * It's an array with document ids as keys (performance considerations)
	 *
	 * @return array
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function matchedDocs()
	{
		require_once 'Zend/Search/Lucene/Exception.php';
		throw new Zend_Search_Lucene_Exception('Wildcard query should not be directly used for search. Use $query->rewrite($index)');
	}

	/**
	 * Score specified document
	 *
	 * @param integer $docId
	 * @param Zend_Search_Lucene_Interface $reader
	 * @return float
	 * @throws Zend_Search_Lucene_Exception
	 */
	public function score($docId, Zend_Search_Lucene_Interface $reader)
	{
		require_once 'Zend/Search/Lucene/Exception.php';
		throw new Zend_Search_Lucene_Exception('Wildcard query should not be directly used for search. Use $query->rewrite($index)');
	}

	/**
	 * Query specific matches highlighting
	 *
	 * @param Zend_Search_Lucene_Search_Highlighter_Interface $highlighter  Highlighter object (also contains doc for highlighting)
	 */
	protected function _highlightMatches(Zend_Search_Lucene_Search_Highlighter_Interface $highlighter)
	{
		$words = array();

		$matchExpression = '/^' . str_replace(array('\\?', '\\*'), array('.', '.*') , preg_quote($this->_pattern->text, '/')) . '$/';
		if (@preg_match('/\pL/u', 'a') == 1) {
			// PCRE unicode support is turned on
			// add Unicode modifier to the match expression
			$matchExpression .= 'u';
		}

		$docBody = $highlighter->getDocument()->getFieldUtf8Value('body');
		require_once 'Zend/Search/Lucene/Analysis/Analyzer.php';
		$tokens = Zend_Search_Lucene_Analysis_Analyzer::getDefault()->tokenize($docBody, 'UTF-8');
		foreach ($tokens as $token) {
			if (preg_match($matchExpression, $token->getTermText()) === 1) {
				$words[] = $token->getTermText();
			}
		}

		$highlighter->highlight($words);
	}

	/**
	 * Print a query
	 *
	 * @return string
	 */
	public function __toString()
	{
		// It's used only for query visualisation, so we don't care about characters escaping
		if ($this->_pattern->field !== null) {
			$query = $this->_pattern->field . ':';
		} else {
			$query = '';
		}

		$query .= $this->_pattern->text;

		if ($this->getBoost() != 1) {
			$query = $query . '^' . round($this->getBoost(), 4);
		}

		return $query;
	}
}

